I. Field of the Invention
This invention relates to rotatable valves used to control fluid flow through a device and, in particular, to a unique stem configuration associated with the rotatable valve which creates a rigid connection between the valve handle and valve member.
II. Description of the Prior Art
Rotatable valves are traditionally used to control the flow of fluids between a fluid source and a fluid device. Such valves may simply provide for turning the flow on or off or for controlling the flow rate according to the degree of rotation. Prior known valves have included ball valves and barrel valves. The conventional valves will include a rotatable valving member disposed in a valve chamber having a fluid inlet and a fluid outlet. Similarly, the valve member will include an inlet and outlet which can be aligned with the chamber inlet and outlet to block or permit flow through the valve. The inlets and outlets can be axially aligned or may be disposed at an angle to each other.
Manipulation of the valve member is facilitated by a valve handle which is connected to the valve member. Specifically, the handle will be connected to a valve stem which extends out of the valve chamber. The handle can be attached to the stem in many ways but must be capable of transmitting rotational torque through the stem to the valve member. In the past, simple fasteners have been used to connect the handle to the valve stem. Such a connection is suitable in applications where a large diameter stem member was used or the external member was metallic. Additionally, in valve assemblies which require increased rotational torque to rotate the valve member, simple connections can fail leaving the user without the ability to manipulate the valve. Furthermore, in prior known valve members which require substantial rotational torque, the valve stem may flex, twist or strip all together. This is particularly a concern in valve assemblies which are not frequently actuated and the member tends to “stick” in the chamber.